Wiping blade for coating devices



June 3, 1952 E. WARNER WIPING BLADE FOR COATING DEVICES Filed March 16, 1949 INVENTOR Edgar War BY I if ner fl ATTORNEY Patented June 3, 1952 VVIPING' BLADE FOR COATING DEVICES EdganWarner, Midd-letown,70hio ,;assignon to. Thc Champion; Paper: an ibre fiompamye Hamil-= ton flhioea c rporat n t Ohio Appliea'tibn'Mr' ich 16, 19l9',"-Serial- Not-"81,79 1

6 :Claims. 1

The :present invention relates 'to '-.wi?ping blades such as-are' sometimes used "in: coatingmachines;

and; has particularlyi reference :to blades: of the type in lwhich the wiping edge i-is formedor .a

rotating rod;

Thewbject: iof the invention is to provide an improved-structure for blades oi this type, a structure which-wi11 make it possible to hold the rotatingrod accurately: and firmly in position at all points throughout its working lengthgre'gard less-of: whether or not the material: on which said blade opera't-es-si in :contact theifewith :1 asstructure Pinlzwhich l the rods can -be positively held straight or bowed: as desired; in lw-hi'chv' the: rod can be aconstrained to rotate with'out wobble Jor eccentricity in a positionwhich may be fixed at allllpoints throughout its: working length; in which, 'in:'spite ofv this constraint, the-rodcan be freely rotated without sticking: and' without chatter; in'which ro'dsdown 'to-one-ei'ghthiinchl' or even less in diameter can beheld as described;

andfa structure whichncan be easily and cheaply m'anuf'acturedzsc that, if desired, the entire blade structureicanfbethrown away and economically" replaced when thelrod becomes-worn or damaged in use; Another object: is to'provide astructure of the type described which can-be easily, quickly; accurately, and cheaply produced and assembled from parts of ready availability? A further object is to provi'deasimple, quick; and; accurate method 1 of making abl'adestructure-of the aforesaid type. Other objects. and advantages cfflthe: invention will be apparent from the following "description;

The structure" in whichI have-found it: possible to attain these objects and secure these advantages comprises a rotating 1 rod and ,a bearing r therefor which-is continuousthroughoutthe working length of the rod. This .bearing is formed of two strips of metal which are in"con"-.

tact with -each other throughout alsubstanti'al laterally from the-' bearing without a substantial.

flexure' of the strips. A-fixed' cap is provided at each end of the bearing: to 1 positively prevent the starting of any such lateral removal 2a which mightfotherwise take place "progressivelyalong its ilengthi 'byJa mere. local bending Jottthe strips: The I terminal edges of these strips are talsoin "close contact with the surface "of the rod. In order tomake this condition more durable; theforiginal shaping of the strips is advantageously "such as to necessitatef'aslight bending back of these: terminal edgesto: make rcom ior the rod; so that these-edges are then held against: the'surface cof: the rod by a livespringing: action in the: metal of the strips. These edges thus continuously wipe the; red as itrrotates. and, :if the rod :is smooth; prevent: the entrance: of:

any coating material or other foreign matter-intothe hearing. The body of the blade structure-is formedioi'two metal bars between whichthe fiat portions Ofii'thfi two strips are rigidly held by rivetingspot Welding-"or equivalent. These; twobars': are: preferably disposed in. parallel relationship, sc that itheouter'rsurfaces of the blade structure are parallel. andthe blade can be more readily=andifirmlyi held in the "desired position;

The t'bars are-of. approximately the same "length: as the strips which form the bearing-for the. rod, and zshouldibe somewhat longer than :the m'axie. mumixintended"working length of the rod. The: ro'd it'self normally extends somewhat beyond one or'both 'endsl of the 'oth'erxparts of the structure so that suitablerdrivingand longitudinallocating;'

devices :may be applied. Since such devices are welliknown 'and'form no part of the presentinven-ti'onythey will: not be-further described;

Thazzmeth'od of. the invention involves-:1 first. welding itogether the. ;two :metal bars "and the spacer between:them,":atone edge thereof: draw ing two metal strips, .each about. half the thickness lnflsaid Jsp'acer; through a die :to shape the metal :near :one edge oi'each Ito forma half? bear ing fori'the cylindrical :rod placing-said two strips: .facetogethertwith the iunshaped portions in contact 'with each other and" the shaped- .po'r tions' inicontact "with the-fopposite sides :of the cylindrical rod; holding thesethree parts firmly. in that position and inserting the unshapedrportions :ofritlie two stripsbetween'the unwelded" edges of *said metal bars, up to the shaped: portions iofthe strips; holding-the parts: firmly in that position and spot welding the strips and: bars together at intervals throughout their length;

The construction will be better understood. by referenceto the accompanying; drawing inwvhlchz- Fig-.11, is a cross: sectional view of the-structuretaken onil-ine -il otFigi 2. i Fig. 2 is. a side-view of the-strueture with part broken aways Fig-,3

outward'to admit the rod II.

l is a fragmentary sectional view, to a larger scale,

sired, and the terms rod, round rod, and

cylindrical rod as used herein are to be understood to refer to rods of circular cross section whether smooth surfaced or not, as the herein described construction is equally applicable to all,

the qualification round or cylindrical being used to distinguish from rods of polygonal cross section. In use this rod is rotated either intermittently to any desired degree at any desired intervals, or continuously at any desired speed,

usually slow, by means which form no part of the present invention and will not be further described.

The rod H is held in position by suitably shaped portions 12 and I3 of metal strips l4 and I5 respectively. These portions of the strips are I shaped to form a bearing in which the rod u can be rotated. Care should be taken that the terminal edges l6 and I1 of the strips l4 and ii are in close contact with the surface of the rod ll. This contact is, in general, more easily assured and maintained if the initial shaping of portions [2 and [3 has been such that the terminal edges I6 and I! have to be sprung slightly The edges l6 and H are then held in contact with the surface of H sumcient to perform the wiping, doctoring, or

. other action for which the blade is to be used.

The width of arearequired to be exposed depends on the diameter of red I l, and on the form ate. If it is to operate against a relatively rigid cylindrical surface of moderate or small radius,

a minimum of space will be required between edges [6 and ii. If the diameter of the cylindridicated in Fig. 3, the edges l6 and I! must have sufficient angular spacing to clear the surface of I and type of surface against which it is to operthe web. It is frequently of advantage, for this purpose, to bevel the corners of the edges l6 and H as indicated at 2|. Theportion of the surface of rod H exposed between edges 16 and IT should, however, always be materially less than half of the rod surface, so that the distance between edges IB and I1 is materially less than the diameter of the rod, in order to hold the rod positively in place without depending on pressure of the Web 20 or other work to hold it in place against its support.

The metal strips used are, in many cases, sufficiently flexible to permit the rod II to be re- 1 moved laterally, between edges 16 and IT, by springing of the metal of the strips. If this removalis started at one end and is carried progressively along the length of the rod, it requires only local flexure of the formed strips l2 and I3. 'In order to prevent this possibility, I prefer to provide at each end of the structure,

means for positively holding the rod ll against lateral removal. These means may be of any 1 form desired but I find the type shown in Figs. 1

,. spot welds.

and 2 to be convenient. As illustrated, each consists of a U-shaped band 25 which holds rod ll against any tendency to lift out of the bearing provided by formed strip portions [2 and I3. The bands 25 as shown extend across the full width of the blade structure, but if desired may be much shorter, as they need only be long enough to be firmly attached to the structure, as hereinafter more particularly described. It is to be noted that these are placed only at the ends, safely beyond the extremities of the working length of the rod. When the ends of rod II are thus held in place, any tendency which may remain for the intermediate portion of the rod to escape is readily resisted by the stiffness of the formed strips l2 and [3.

The blade structure is held together and given its stiffness by metal bars 26 and 21. These hold the fiat portions of strips l4 and I5, which are in contact with each other, in place between them. In'case these flat portions l4 and I5 are, as illustrated in the drawing, of less width than the bars 26 and 21, it is desirable to have these bars separated at their other edges by a spacer 2B or multiplicity of spacers, or one or more projections formed on one or both of the bars 26 and 21, in order that the outer surfaces of bars 26 and 21 may be parallel to facilitate the holding of the blade in position for use. The strips, bars, and spacers, if used, are held rigidly together by any suitable fastening means such as rivets or spot welds 30, to form a unitary blade structure which firmly supports and accurately holds the rod H in place throughout its length, but permits it to be freely rotated as required in use.

The metal strips which hold rod ll may be given the form shown in Figs. 1 and 3 by any suitable means, and can be conveniently formed by drawing fiat strips through suitable dies. The shaped portions may be the same length in each, as shown in Fig. 1, or one may be shorter than the other, as shown in Fig. 3, in cases where the angles of approach to and departure from the blade by the surface on which the blade operates, are not equal. The straight portions of the strips I4 and I5 may be as wide as the bars 26 and 21, in which case no spacer 28 or equivalent is necessary, or they may be only wide enough for the necessary rivets or They should be thick enough and stiff enough to hold the rod II accurately centered against all forces which may be expected in normal operation. I have found metal of half-hard temper, so-called, to be suitable in many cases. Though the fiat portions of these strips are preferably in contact with each other. they may if desired for any reason, be separated by a spacer, if it is not too thick with reference,

to the diameter of rod H. I have ordinarily found it more convenient to use two separate strips I5 and I5 though they may, if desired, be made of a single double width strip formed and doubled on itself in the middle, though this method requires somewhat more careful workmanship than that already described.

' The bars 26 and 21 may be of any width and thickness required to give the structure the required rigidity, when the required length of the blade is taken into consideration. If it is desired that the rod be bowed in use, the bars 25 and 2! may be given the slight curvature required, or they may be straight and then sprung in clamping and held under strain with the desired amount of bow.

The structure is adapted to use with rods of from inch, or even less, in diameter up to any size which requires lateral support intermediate its ends in order to hold the required form over the required length, specifically in those cases when an enlarged diameter, or crown, in the center of the span is inadequate for this purpose.

The entire structure may be made of any metals suitable for the purpose intended. For many purposes I have found chromium plated steel suitable for rod II. The shaped bearing strips l2 and I3 may be made of steel, but if the blade is to be used under corrosive conditions a corrosion-resistant metal such as, for example, stainless steel, is generally desirable. Metal for the other parts should be similarly chosen with regard to the requirements which it will have to meet in use. The present invention, however, is not dependent on any specific material.

The construction shown is not only successful, satisfactory, and durable in operation, it is also well adapted to ease and rapidity of construction. The strips [4, I5, the bars 26, 21, and spacers 28 are all standard pieces of metal which are available on the market rolled or drawn to the necessary dimensions. The strips 14 and I5 are then drawn through a suitable die to give them the form shown at 12 and 13. The spacer 23 is next assembled between bars 25 and 21 which are carefully aligned and the three parts spot welded in place. The strips l4 and I5 are then placed together with the bearing portions [2, IS on opposite sides of rod 1 I and slipped in between bars 26 and 21, and held firmly in place while spot welding at intervals throughout the length of the structure. One of the U-shaped retainers 25, which may be suitably bent pieces of cold rolled steel, is then sliped over the structure at each end and spot welded in place. If it is thereafter desired to remove and/or replace rod II, it may be withdrawn and replaced by sliding endwise in the mount.

As an example, I have made blades as described, up to a length of about 20 feet, in which the rod II was of chromium plated tool steel inch in diameter, the strips 14 and I5 were of half-hard stainless steel 0.010 inch thick and inch wide, while bars 26 and 21 were of 0.20 carbon cold rolled steel 0.050 inch thick and 2 inches wide, the whole held together by two rows of spot welds 30 averaging about inch apart. These blades were found to fulfill all of the hereinbefore enumerated objects and to operate successfully for long periods of time, during which the rod II was continuously rotated, in connection with the application of aqueous coating compositions to paper.

I claim:

1. A wiping |blade adapted for use in a coating device, comprising: a cylindrical rod; two strips of metal in contact with each other throughout a substantial proportion of their width, but spread apart near one edge and shaped to form between them a bearing for said rod throughout its working length, the terminal edge of each strip being in close contact with the surface of said rod and substantially parallel with its axis, said terminal edges being spaced to expose a substantial portion, materially less than half, of the surface of said rod; two metal bars of length approximately equal to that of said strips, disposed in parallel relationship, with the flat portions of said strips between them and the rodholding portions extending beyond their edges, said strips and bars being rigidly fastened together to form a unitary firm supporting structure in which said rod is accurately held and freely rotatable.

2. A blade in accordance with claim 1 wherein means are provided at each end, beyond the working length thereof, for positively holding the rod in place in the bearing formed by the shaped portions of the metal strips.

3. A blade in accordance with claim 1 wherein the strips which form the bearing for the rotating rod are so shaped that their terminal edges are held against the surface of the rod by a live springing action in the metal of the strips.

4. A blade in accordance with claim 1 wherein the strips which form the bearing for the rotating rod are substantially identical in form and are symmetrically arranged with reference to the central plane of the blade structure:

5. A blade in accordance with claim 1 wherein the shaped portion of one of the strips which together form a bearing for the rod, extends around a greater portion of the circumference of the rod than does the corresponding shaped portion of the other strip.

6. A'wiping blade adapted for use in a coating device, comprising: a cylindrical rod; two strips of metal, a substantial portion of the width of each strip at one edge thereof being flat, while the portion adjacent the other edge thereof is curved in approximate conformity with a portion of the surface of said rod, said strips being disposed on opposite sides of said rod in position to form, between the curved portions thereof, a bearing, continuous throughout the working length of said rod, in which said rod may be rotated, the terminal edges of the curved portions of said strips being in close contact with said rod and spaced from each other to expose a substantial portion, materially less than half, of the surface of said rod; two metal bars, of length approximately equal to that of said strips, disposed in parallel relationship, with the flat .portio-ns of said strips between them, and the rodholding portions of said strips extending beyond their edges, said strips and bars being rigidly fastened together to form a unitary firm supporting structure in which said rod is accurately held and freely rotatable.

EDGAR WARNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,956,561 Coates May 1, 1934 1,959,027 Hemstreet May 15, 1934 2,033,379 Jenkins et a1. Mar. 10, 1936 2,221,441 Charters Nov. 12, 1940 2,326,283 Bonsall Aug. 10, 1943 2,334,102 Kauppi et a1 Nov. 9, 1943 2,354,033 McGladrey et al. July 18, 1944 

